橡胶轮胎和软管用高强度钢帘线盘条的研发

为了减轻汽车重量,提高燃油消耗,研制了高强度钢帘线用线材。然而,开发高强度钢帘线的难点是必须同时获得高强度和良好的塑性。为了解决这一问题,通过分析拉丝过程中钢丝组织和力学性能的变化,研究了拉丝过程中的分层机理,提高了拉丝的塑性。采用1.0%C过共析钢和优化的拉拔工艺,在实验室可获得4400 MPa级钢帘线。     

Biocomposites of Epoxidized Natural Rubber/Poly(lactic acid) Modified with Natural Fillers (Part I)

The study aimed to prepare sustainable and degradable elastic blends of epoxidized natural rubber (ENR) with poly(lactic acid) (PLA) that were reinforced with flax fiber (FF) and montmorillonite (MMT), simultaneously filling the gap in the literature regarding the PLA-containing polymer blends filled with natural additives. The performed study reveals that FF incorporation into ENR/PLA blend may cause a significant improvement in tensile strength from (10 ± 1) MPa for the reference material to (19 ± 2) MPa for the fibers-filled blend. Additionally, it was found that MMT employment in the role of the filler might contribute to ENR/PLA plasticization and considerably promote the blend elongation up to 600%. This proves the successful creation of the unique and eco-friendly PLA-containing polymer blend exhibiting high elasticity. Moreover, thanks to the performed accelerated thermo-oxidative and ultraviolet (UV) aging, it was established that MMT incorporation may delay the degradation of ENR/PLA blends under the abovementioned conditions. Additionally, mold tests revealed that plant-derived fiber addition might highly enhance the ENR/PLA blend’s biodeterioration potential enabling faster and more efficient growth of microorganisms. Therefore, materials presented in this research may become competitive and eco-friendly alternatives to commonly utilized petro-based polymeric products.     

Characterization of barium titanate reinforced acrylonitrile butadiene rubber composites for flexible electronic applications: influences of barium titanate content

The aim of this study was to develop high dielectric constant flexible polymers with a highly efficient and cost‐effective approach using acrylonitrile butadiene rubber (NBR) as the polymer matrix and barium titanate (BT) as the high dielectric constant filler. The BT powder was synthesized with a solid‐state reaction and was characterized using a particle size analyzer, XRD, SEM and Fourier transform infrared spectroscopy. NBR/BT composites were fabricated using an internal mixer with various BT loadings up to 160 phr. The influence of BT loading on the cure characteristics and mechanical, dynamic mechanical, thermal, dielectric and morphological properties was determined. The incorporation of BT in the NBR matrix shortened scorch time and increased delta torque. The mechanical properties, thermal stability and dielectric constant were greatly improved and increased with BT loading. The results suggest that the reinforcement effect was achieved due to strong hydrogen bonding or polar–polar interactions between NBR matrix and BT filler. This is further corroborated by the good dispersion of BT filler in the NBR matrix observed with SEM imaging. These findings can be applied to produce high‐performance dielectric elastomers. © 2020 Society of Industrial Chemistry     

海上热采防砂封隔器研制与室内试验

海上稠油热采开发过程中,通常采用蒸汽吞吐的方式进行原油开采。为满足稠油热采长效密封要求,研制了HPHT-215型热采防砂封隔器。封隔器胶筒采用特制的氟硅基复合材料+玻璃纤维网结构,并开展了材料性能评价测试。通过有限元分析和室内胶筒组合测试,对胶筒材料和组合结构进行了评价优化。室内全尺寸整机测试表明:封隔器能够满足耐温350 ℃、耐压21 MPa密封性能要求,并开展了高低温多轮次密封性能评价测试。该型热采防砂封隔器的研制成功,为海上稠油蒸汽吞吐多轮次开发提供了保障,具有广泛的应用前景。     

Synthesis and characterization of natural rubber-based telechelic oligomers via olefin metathesis

Metathesis degradation and functionalization of natural rubber (NR) were conducted with 1-hexene, 1-octene, 1-decene, 1-dodecene, trans-stilbene, and 4,4′-dibromo-trans-stilbene as chain transfer agents (CTAs) in presence of Grubbs 2nd generation catalyst to generate NR-based telechelic oligomers that had been a long-lasting challenge due to the structure and compositions of NR with various impurities. Orthogonal experiments were applied and the effects of the CTA type, CTA concentration, catalyst concentration, reaction time, and reaction temperature on the formation of telechelic oligomers were studied, indicating that the catalyst concentration was the major factor influencing the number average molecular weights (M_n) and polymer dispersity index (PDI) of telechelic oligomers. The structures of the oligomers were characterized using ¹H NMR, ¹³C NMR, and MALDI-TOF-MS, which confirmed the formation of the designed terminal groups. The results showed that well-defined telechelic oligomers with a M_n of a few thousand and a PDI around 1.6 were obtained, with potential applications in binder, lubricant and many other fields.     

Rubber's dissipated energy quantification used in vibratory insulation and protection systems

In vibratory protection and insulation systems, the major problem consist to choose suitable passive elements (spring, damper, others), which are inserted between the resonator and the exciter which have the role of preventing or reducing the transmission of dynamic forces. This work consists of characterizing a synthetic rubber (SR) sample of hollow circular shape (design requirement) by determining the coefficient of energy dissipation at an average ambient temperature of 20°C with a humidity of 25%. The mechanical load and discharge tests make it possible to draw hysteresis curves through which the dissipation coefficient will be determined, the load values is between 500 and 1000 N, with 30, 60, and 90 mm/min loading speeds and a number of cycles 2, 3, and 5, these values have been chosen so as not to cause the effect of cyclic hardening and softening and also to take into consideration, that the vibration limits movement at 3 cycles, which makes this test different from other tests such as fatigue. The processing of different curves, allows to determine energy dissipation coefficient of rubber specimen and also to examine its variation as a function of load, loading speed, and number of cycles; it is possible to determine other characteristics from this coefficient, such as, damping ratio, dynamic amplification factor, and so on, necessary to study efficiency of protection systems, design, and manufacture, based on the curve of transmissibility of dynamic forces to evaluate performance rubber conditions use.     

脱硫胶粉在乳化改性沥青中的应用

考察了不同规格胶粉及不同脱硫程度的脱硫胶粉对橡胶改性乳化沥青性能的影响,结果表明,采用100目胶粉即可制备出橡胶改性乳化沥青,但乳化沥青的性能较差;采用活化度为50%左右的100目脱硫胶粉制备乳化沥青时,脱硫胶粉的用量相比于胶粉可大幅提高;在通过外掺100目50%左右活化度的脱硫胶粉(质量分数15%,以沥青计,下同)和质量分数2%的苯乙烯-丁二烯-苯乙烯嵌段共聚物改性的乳化沥青中添加质量分数1%的丁苯胶乳,所制备橡胶改性乳化沥青无筛上剩余物,5 d储存稳定性为2.9%,蒸发残留物的25℃针入度、软化点和5℃延度分别为55 (0.1 mm)、64.5℃和22.5 cm,能够满足乳化改性沥青的技术指标要求。     

基于有限元仿真的发泡硅橡胶老化规律研究

通过力学性能测试得到发泡硅橡胶应力应变曲线,结合Ogden(Foam) 3阶超弹本构模型,建立发泡硅橡胶静密封系统的有限元仿真模型,得到大压缩量下发泡硅橡胶的von Mises应力及接触压力分布情况。仿真结果表明:大压缩量下发泡硅橡胶对称中心线位置的von Mises应力、接触压力值较大,在橡胶边缘和靠近限位环处接触应力数值有突增。开展140℃热空气老化试验,测定老化后发泡硅橡胶应力应变曲线,结合有限元仿真模型分析发泡硅橡胶老化后von Mises应力、接触压力的变化规律。结果表明:经过热空气老化后,在一定载荷下发泡硅橡胶等效应力和接触压力均呈增大的趋势。     

New ways to improve the damping properties in high‐performance thermoplastic vulcanizates

The incorporation of viscoelastic materials represents an effective strategy to reduce the vibratory level of structural components. Thermoplastic vulcanizates (TPVs) are a special type of viscoelastic material that combines the elastomeric properties of rubbers with the easy processing of thermoplastics. In the present work, we propose innovative ways to improve the damping properties of high‐performance TPVs by using rubbers with carboxylic functionalities. For that, TPVs from physical blends of carboxylated hydrogenated acrylonitrile butadiene rubber (XHNBR) and polyamide 6 (PA6) were prepared. The chain dynamics of different mixed crosslink systems containing peroxide, metal oxides and hindered phenolic antioxidants were investigated in order to find the most suitable strategy to design a high‐performance TPV system with upgraded damping properties. The results indicate that the damping performance of the TPV system can be tailored by controlling the type and magnitude of the bonding interactions between the mixed crosslink system and the XHNBR rubber phase. Therefore, this study demonstrates the potential of TPV systems containing carboxylic rubbers as high‐performance damping materials. © 2020 Society of Chemical Industry